Advocate staff photo by HEATHER MCCLELLAND -- Bill Cassidy's election results party on Tuesday, Nov. 4, 2014 at the Crowne Plaza Hotel.

Washington The U.S. House Friday approved a Keystone XL pipeline bill by Republican U.S. Rep. Bill Cassidy that’s part of a political drama co-starring him and his Democratic opponent in the Dec. 6 U.S. Senate runoff in Louisiana, incumbent Mary Landrieu.

Meanwhile, Landrieu is lobbying her fellow Democrats to support an identical Senate version of the legislation greenlighting the controversial pipeline in hopes of sending the measure at last to the White House — where aides to Democratic President Barack Obama have strongly indicated he will veto it.

“I believe I have the votes to pass it,” Landrieu said after the House acted Friday, though she stopped short of declaring flatly that she has the necessary support lined up.

What might look like a rare case of collaboration among political opponents — Cassidy and Landrieu — actually amounts to a battle for Keystone bragging rights.

But no matter who gets the credit if the bill clears Congress, an Obama veto would almost certainly doom the proposal in the current lame-duck legislative session, which terminates at the end of this year.

“The case for approving the Keystone XL pipeline is clear and obvious,” Cassidy said on the House floor Thursday during debate on his bill. “This is a perfect example of what the American people have asked us to do.”

The House voted 252 to 161 for the bill, with all six Louisiana delegation members supporting.

Cassidy, a third-term House member from Baton Rouge who ran a close second to Landrieu in Louisiana’s open primary Nov. 4, introduced his version of the Senate Keystone bill this week. The ruling House Republican leadership rushed it through the approval process. The House has voted for similar measures eight times before, only to see them languish in the Democratic-majority Senate.

Landrieu said she was “proud” that the House passed the Cassidy bill, adding, “Imitation is the best form of flattery.”

The pipeline would bring “dirty” tar-sands oil from Canada to refineries on the Texas Gulf Coast. Supporters of the pipeline say it will create jobs and reduce American dependence on oil imported from unfriendly and unstable foreign countries outside North America.

Opponents fear it will result in increased carbon emissions, and the project has been stalled by Obama, whose approval is required because the pipeline crosses an international border.

Obama has said that before he decides on the pipeline, he wants to wait for completion of a State Department review and for resolution of a legal challenge to the pipeline’s route now before the Nebraska Supreme Court. Cassidy’s bill would effect approval of the project.

In her campaign against Cassidy, Landrieu has touted the influence she has gained in the Senate by virtue of her seniority — in particular, her appointment early this year as chairwoman of the Energy and Natural Resources Committee, with its oversight of the oil and gas industry central to the Louisiana economy.

Democratic election defeats in other states Nov. 4 mean they will lose the Senate majority in the new Congress convening in January and, with it, the power to determine the energy committee chairman. Landrieu still would like to show she can get things done for her state, where support for the pipeline is strong. In the process, she can demonstrate her independence from Obama; Cassidy has focused his campaign on linking her to the president, who is widely unpopular in Louisiana.

Landrieu sponsored a Keystone bill that she moved through the energy committee in June. But that bill has not come up for a floor vote due to partisan wrangling and objections from a majority of the Democrats who currently rule the Senate.

On Wednesday, she took to the Senate floor to press for a vote on a similar Keystone bill by John Hoeven, R-N.D. This time, the Senate Democratic leadership agreed and has set a vote for as early as Tuesday. The movement in the Senate spurred Cassidy into action in the House.

Under the Senate rules for the legislation, it will take 60 votes to pass the bill, meaning Landrieu has to round up 14 additional Democratic votes besides her own to combine with the expected unanimous support of the 45 Republicans.

She is said to be close — maybe a vote or two shy. If both the House and Senate approve identical measures, then the proposal can go directly to the White House, with no need to resolve the differences that are typical in such cases. Landrieu has said she’s OK with having Cassidy’s name on the legislation that wins final passage.